RV Fridge / Household Fridge

I may be missing something but every house unit I checked that were in RVs consumed more power for the same size. The ratings are on a label inside the door. Probably the best number would be KW per year. However, you can bet the #s are probably based on a house unit sitting in a 70 degree house.

residential 120v compressor fridge is cheaper to operate on 120v power than an RV fridge heating a 345w heating element
i remember putting a Kill-A-watt meter on my fridge 4 or 5 yrs ago and testing it for a week during the summer

my fridge draws about 100w when running after startup
of course it all depends on the size of your fridge

Typically RV absorption fridges are much less energy efficient on AC power than decent household compressor fridges, by a factor of perhaps three or four. Modern energy star fridges use somewhere around 1 kWh per day or so. You can look on the efficiency labels to get a reasonable feel for that, at least in an approximate sense.

The current rating for the residential fridge is a worst-case steady state current, I suspect, and probably has more to do with the defrost heater than the compressor. The compressor I understand often rates somewhere around 80-100W running power (and, like many electric motors, a lot higher surge current for starting).

Hi RV Sam,

It depends on the duty cycle. My RV fridge is 2:3 so it is 'on' 40 minutes per hour. A residential may have a much lower duty cycle.

My RV absorption fridge uses 5.7 kwh per day.

RV Sam wrote:
Can anyone comment on this please. RV unit says 2.7amps... House unit same size says 2.9amps. I have a "feeling", going to bring my meter and check this weekend, that the House unit will burn less power than the RV unit because of the difference in the way they make things cold. Has anyone done any test on this ?

If this is a hypothetical question, maybe google knows. Maybe you can understand what Mex just wrote.

If it's about saving kilowatts, it's likely moot. IOW, the difference is likely tiny.

Freon is infinitely more efficient than hydrogen saturated ammonia (absorbsion). As a curious point however, an electric motor powered ammonia ice plant is significantly more efficient than even a Freon 12 plant, using the same horsepower compressor.

Wuuwee, take a hospital, start calculating the relative cost differential between freon A/C and steam boiler driven lithium bromide absorbsion chillers and the calculations progress to a mind numbing degree.

But gas refrigeration cannot be realistically compared to Freon refrigeration because there's a lot more too it than Neanderthal-grade BTU comparisons. Freon refrigeration is light-years more uniform especially in warm to very warm climes. Increasing condenser capacity is easy with Freon. But insanely costly for absorbsion gas. Then there is the problem of how to control and contain tiny, angry, hydrogen atoms.

RV Sam wrote:
Ya Mex I guess the Household unit i am referring to could be a 12VDC. But no. Both amp loads mentioned are 120VAC. That really isn't the issue. Maybe never explained myself clearly. My question is, does a unit that cools via ammonia ( RV unit ) use more kilowatts overall then a Household freon / compressor unit ? Thanks.

Possibly as the RV unit uses an electric heating element to cool. The element alone can be 1000-2000 watts. BUt what you loses with a residential fridge is the propane option. To me the propane option is best while boondocking

Ya Mex I guess the Household unit i am referring to could be a 12VDC. But no. Both amp loads mentioned are 120VAC. That really isn't the issue. Maybe never explained myself clearly. My question is, does a unit that cools via ammonia ( RV unit ) use more kilowatts overall then a Household freon / compressor unit ? Thanks.

We talking alternating current or battery current? You're retaining 99% of needed info between your ears :)

What kind of refers are we talking about?